From 19bfaf2b58060d2d3227e3200bd833d9e9b08e1c Mon Sep 17 00:00:00 2001
From: David Sobek <david.sobek@picknik.ai>
Date: Fri, 24 Apr 2026 13:25:28 -0600
Subject: [PATCH] Handle empty vector toStr case

---
 include/behaviortree_cpp/basic_types.h |  4 ++++
 tests/gtest_ports.cpp                  | 19 +++++++++++++++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/include/behaviortree_cpp/basic_types.h b/include/behaviortree_cpp/basic_types.h
index 5907d846f..9e266022c 100644
--- a/include/behaviortree_cpp/basic_types.h
+++ b/include/behaviortree_cpp/basic_types.h
@@ -281,6 +281,10 @@ template <typename T>
   {
     try
     {
+      if(value.empty())
+      {
+        return "";
+      }
       using InnerType = typename is_vector<T>::ValueType;
       std::stringstream ss;
       for(auto it = value.begin(); it != --value.end(); ++it)
diff --git a/tests/gtest_ports.cpp b/tests/gtest_ports.cpp
index cbe644aaf..50e05ad7f 100644
--- a/tests/gtest_ports.cpp
+++ b/tests/gtest_ports.cpp
@@ -6,13 +6,28 @@
 
 using namespace BT;
 
-TEST(toStr, ConvertsVectors)
+TEST(toStr, ConvertsIntVector)
 {
   std::string val_str;
-  ASSERT_NO_THROW(val_str = BT::toStr(std::vector<int>{ 1, 2, 3, 4 }));
+  ASSERT_NO_THROW(val_str = toStr(std::vector<int>{ 1, 2, 3, 4 }));
   EXPECT_EQ(val_str, "1;2;3;4");
 }
 
+TEST(toStr, ConvertsStringVector)
+{
+  std::string val_str;
+  ASSERT_NO_THROW(val_str =
+                      toStr(std::vector<std::string>{ "hello", "", " ", "world", "!" }));
+  EXPECT_EQ(val_str, "hello;; ;world;!");
+}
+
+TEST(toStr, ConvertsEmptyVector)
+{
+  std::string val_str;
+  ASSERT_NO_THROW(val_str = toStr(std::vector<std::string>{}));
+  EXPECT_EQ(val_str, "");
+}
+
 class NodeWithPorts : public SyncActionNode
 {
 public: